| XDPS-400 distributed control system is used as background in the paper. The system is used by the DCS systems engineering of 240T/H CFB (Circulating Fluidized Bed) Boiler 3 stove 2 plane of Luhua Hengsheng thermoelectric company and is assembled with imported pieces. The optimal design of 240T/H CFB coal-fired boiler control system is introduced and the range of system control covers with the DAS, MCS, SCS, FSSS function of 240T/H CFB 3 stove 2 plane.CFB boiler has many advantages that traditional coal-fired boilers have not, such as high combustion efficiency, wide fuel adaptability, desulfurization in furnace, good load regulation. It is better to solve the high energy consumption, high pollution and other problems. In many developed countries CFB boiler has been widespread applied. Since the early 1980s, the study and promotion of this boiler are begun in our country and used as a cross-century and updated coal-fired technology.However, the CFB combustion mechanism is very complex, which contains a range of topics in basic research. Combustion temperature is influenced by many factors and have complicated coupling with other systems, but the system has strong time-variability. Although there are various types of CFB have been input into operation and use in domestic, the level of automatic control is lower than foreign, especially in combustion control system that high-performance is hard to be achieved at desired target. At present, the introduction of advanced technology and information from abroad is difficult. Therefore, it is urgent to explore the control schemes that are suitable for CFB boiler combustion system. Some research in this aspect is done in the paper.The problem of multivariable closely coupled and strong time variability in the circulating fluidized bed combustion boiler system are aimed at in the paper. The fuzzy between the close coupling variables is fined by in-depth study of the conditions of the boiler combustion. On basis of analyzing the existing boiler control system algorithm and combining with fuzzy logic control theory, a fuzzy logic control program for CFB boiler fuel control is present. Compared with the conventional PID control of mathematical model in CFB boiler, a very practical mathematical model is formed, which is fuzzy logic self-tuning PID complex control algorithms. The design of whole combustion control system is completed to solve the contradiction between load control and temperature control in better. The experiment results show that the desired results of combustion control system is achieved and it can be used in industrial field.The key technology in the paper is: the use of fuzzy controller. Fuzzy correction is done according to each analog, meanwhile the fluctuations of fuel thermal value is changed into the change of fuel feed by fuel controller to maintain the needed combustion rate. The appliance value of the subject is that fuzzy control which is used as CFB boiler control is present, which is aimed at the problems of low combustion efficiency of CFB boiler, not meet internationally recognized standards, and unreasonable temperature distribution lines. The fluctuations of operating parameters are reduced and a more stable combustion conditions is achieve which result in lower costs and the purpose of saving coal. This is the core of the paper.Actual operating results show that operating costs is lower and operating efficiency is improved with the design of 240T/H CFB boiler combustion control. |
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